#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
int n,d,m;
vector <pair<ll,ll>> l1;
bool check(ll a, vector <ll> f_table){
ll answ = 0;
for (int i =1 ; i <= (n-d); i++){
if (f_table[i] < a){
answ -= min(answ, a - f_table[i]);
}
else{
answ += f_table[i] - a;
}
}
if (answ >= 1){
return false;
}
else{
return true;
}
}
int main(){
cin >> n >> d >> m;
vector <ll> f_table(n+1,0);
vector <deque <ll>> final(n+1);
for (int i = 0; i < m; i++){
ll a;
cin >> a;
l1.push_back({a, i+1});
f_table[a] += 1;
final[a].push_back(i+1);
}
sort(l1.begin(), l1.end());
ll l = 1;
ll r = m;
while (l!=r){
ll mid_point = (l+r)/2;
if (check(mid_point, f_table)){
r = mid_point;
}
else{
l = mid_point + 1;
}
}
vector <ll> counter(n+1, 0);
queue <ll> idk;
for (int i = 1; i <= n - d; i++){
if (final[i].size() > l){
while (final[i].size() > l){
ll current = final[i].back();
final[i].pop_back();
idk.push(current);
}
}
else{
for (int j = 0; j < idk.size(); j++){
ll current = idk.front();
idk.pop();
final[i].push_front(current);
if (final[i].size() > l){
ll now = final[i].back();
final[i].pop_back();
idk.push(now);
}
}
}
}
cout << l << "\n";
for (int i = 1; i <= n; i++){
for (auto &p : final[i]){
cout << p << " ";
}
cout << 0 << "\n";
}
}
